Refactored the DDD-hex example to define own structs for each of the …

…operations available.

domain-driven-hex/cmd/beer-server/main.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/katzien/go-structure-examples/domain-driven-hex/http/rest"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/listing"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/adding"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/reviewing"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/storage/memory"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/storage/json"
+)
+
+// StorageType defines available storage types
+type Type int
+
+const (
+	// JSON will store data in JSON files saved on disk
+	JSON Type = iota
+	// Memory will store data in memory
+	Memory
+)
+
+func main() {
+
+	// set up storage
+	storageType := JSON // this could be a flag; hardcoded here for simplicity
+
+	var adder adding.Service
+	var lister listing.Service
+	var reviewer reviewing.Service
+
+	switch storageType {
+	case Memory:
+		s := new(memory.Storage)
+
+		adder = adding.NewService(s)
+		lister = listing.NewService(s)
+		reviewer = reviewing.NewService(s)
+
+	case JSON:
+		// error handling omitted for simplicity
+		s, _ := json.NewStorage()
+
+		adder = adding.NewService(s)
+		lister = listing.NewService(s)
+		reviewer = reviewing.NewService(s)
+	}
+
+	// set up the HTTP server
+	router := rest.Handler(adder, lister, reviewer)
+
+	fmt.Println("The beer server is on tap now: http://localhost:8080")
+	log.Fatal(http.ListenAndServe(":8080", router))
+}

domain-driven-hex/cmd/sample-data/main.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"fmt"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/storage/json"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/adding"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/reviewing"
+)
+
+func main() {
+
+	var adder adding.Service
+	var reviewer reviewing.Service
+
+	// error handling omitted for simplicity
+	s, _ := json.NewStorage()
+
+	adder = adding.NewService(s)
+	reviewer = reviewing.NewService(s)
+
+	// add some sample data
+	adder.AddSampleBeers()
+	reviewer.AddSampleReviews()
+
+	fmt.Println("Finished adding sample data.")
+}

domain-driven-hex/http/rest/handler.go

@@ -0,0 +1,114 @@
+package rest
+
+import (
+	"net/http"
+	"github.com/julienschmidt/httprouter"
+	"encoding/json"
+	"strconv"
+	"fmt"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/listing"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/adding"
+	"github.com/katzien/go-structure-examples/domain-driven-hex/pkg/reviewing"
+)
+
+func Handler(a adding.Service, l listing.Service, r reviewing.Service) http.Handler {
+	router := httprouter.New()
+
+	router.GET("/beers", getBeers(l))
+	router.GET("/beers/:id", getBeer(l))
+	router.GET("/beers/:id/reviews", getBeerReviews(l))
+
+	router.POST("/beers", addBeer(a))
+	router.POST("/beers/:id/reviews", addBeerReview(r))
+
+	return router
+}
+
+// addBeer returns a handler for POST /beers requests
+func addBeer(s adding.Service) func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+		decoder := json.NewDecoder(r.Body)
+
+		var newBeer adding.Beer
+		err := decoder.Decode(&newBeer)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		s.AddBeer(newBeer)
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode("New beer added.")
+	}
+}
+
+// addBeerReview returns a handler for POST /beers/:id/reviews requests
+func addBeerReview(s reviewing.Service) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+		ID, err := strconv.Atoi(p.ByName("id"))
+		if err != nil {
+			http.Error(w, fmt.Sprintf("%s is not a valid Beer ID, it must be a number.", p.ByName("id")), http.StatusBadRequest)
+			return
+		}
+
+		var newReview reviewing.Review
+		decoder := json.NewDecoder(r.Body)
+
+		if err := decoder.Decode(&newReview); err != nil {
+			http.Error(w, "Failed to parse review", http.StatusBadRequest)
+		}
+
+		newReview.BeerID = ID
+
+		s.AddBeerReview(newReview)
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode("New beer review added.")
+	}
+}
+
+// getBeers returns a handler for GET /beers requests
+func getBeers(s listing.Service) func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+		w.Header().Set("Content-Type", "application/json")
+		list := s.GetBeers()
+		json.NewEncoder(w).Encode(list)
+	}
+}
+
+// getBeer returns a handler for GET /beers/:id requests
+func getBeer(s listing.Service) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+		ID, err := strconv.Atoi(p.ByName("id"))
+		if err != nil {
+			http.Error(w, fmt.Sprintf("%s is not a valid beer ID, it must be a number.", p.ByName("id")), http.StatusBadRequest)
+			return
+		}
+
+		beer, err := s.GetBeer(ID)
+		if err == listing.ErrNotFound {
+			http.Error(w, "The beer you requested does not exist.", http.StatusNotFound)
+			return
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(beer)
+	}
+}
+
+// getBeerReviews returns a handler for GET /beers/:id/reviews requests
+func getBeerReviews(s listing.Service) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+		ID, err := strconv.Atoi(p.ByName("id"))
+		if err != nil {
+			http.Error(w, fmt.Sprintf("%s is not a valid beer ID, it must be a number.", p.ByName("id")), http.StatusBadRequest)
+			return
+		}
+
+		reviews := s.GetBeerReviews(ID)
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(reviews)
+	}
+}

domain-driven-hex/pkg/adding/beer.go

@@ -0,0 +1,9 @@
+package adding
+
+// Beer defines the properties of a beer to be added
+type Beer struct {
+	Name      string    `json:"name"`
+	Brewery   string    `json:"brewery"`
+	Abv       float32   `json:"abv"`
+	ShortDesc string    `json:"short_description"`
+}